It is important what you have written here saddlers. If the fire is below you and see smoke rising, you become aware and effectively become "Affected" by fire. Granted on a pshycological level but none the less your behavior will change.
I think the strategy works well if people aren't aware of a fire in their building, the moment you become aware, you wish to leave. The investigation into the deaths of the fire fighters in the Stevenage high rise fire in 2005 recommended that sounders and break glass units were removed from common areas. The alarms caused confusion.
I recently attended the aftermath of a sheltered accomodation fire and in my opinion if all occupants had stayed in their flats, no-one would have been hurt. Those who left their flats moved smoke through doors that would have otherwise been closed (Ie corridoors)